The present invention is concerned with carbapenem and 1-methylcarbapenem antibiotics having a quaternary mono- or bicyclic heteroarylium alkyl group which is internally alkylated in the 2-position.
Thienamycin is a known carbapenem, broad spectrum antibiotic of the formula: ##STR2## Other derivatives of A are also known.
The present internally alkylated mono- or bicyclic 2-quaternary heteroarylalkyl substituted carbapenems are believed to have an antibiotic spectrum comparable to A.